Millions of people use complementary therapies in the UK, and demand is growing. About half of GPs now provide some kind of access to such treatments.

Osteopathy, chiropractic and acupuncture can aid those with conditions such as back pain, the report concluded.

Herbal medicines were found to help people with conditions including arthritis, colds, depression and heart and circulatory problems.

But the report found the benefits of homeopathy - a therapy which works on the principle of treating like with like - are more questionable.

The report says that, as back pain alone accounts for 200 million lost days from work each year, costing £11 billion in lost production, it would be cost-effective to widen the use of complementary therapies in the NHS.

Deprived areas

Launching the report, Mr Smallwood said: "The weight of evidence we have examined suggests that complementary and alternative medicines could play a larger role in the delivery of healthcare, and help to fill recognised gaps in healthcare provision.

There is a shortage of therapies such as acupuncture in deprived areas, the report says

But he said many people in less well-off areas did not have access to such treatments.

"Complementary medicine remains out of reach for many low income families, those who would have found most benefit from its provision."

He called for the NHS's drugs watchdog, the National Institute for Health and Clinical Excellence, to assess the cost-effectiveness of complementary therapies.

Mr Smallwood's report also calls on the government to boost funding for the therapies on the NHS.

The Department of Health says it is committed to introducing regulation in the area.

Prince Charles, an enthusiast for alternative medicine, commissioned Mr Smallwood to compile a report nine months ago, but has had no involvement in its preparation since then.

A spokeswoman from Clarence House said the Prince was very grateful to Mr Smallwood and the FreshMinds research consultancy, for producing the report.

She said: "By commissioning this report the Prince hoped to further encourage an informed debate about how an evidence-based integrated approach to health, which draws on the best of both orthodox and complementary medicines, might offer wider benefits."

'Not up to scratch'

But Prince Charles' involvement has led some experts to question whether the study was biased in favour of these treatments.

Edzard Ernst, professor of complementary medicine at the University of Exeter's Peninsula Medical School told BBC Radio 4's Today programme he had concerns over the report.

Professor Ernst was interviewed during research for the report, but asked for his contribution to be withdrawn.

He said a draft version which he had seen "wasn't really up to scratch".

But Mr Smallwood said Professor Ernst's comments were unfair because he had not seen the final version.

He also denied he had any "axe to grind" in terms of manipulating the data to fit certain conclusions.

Dr Jane Maher, chief medical officer at Macmillan Cancer Relief, welcomed the report but said: "It's clear now more research needs to be carried out on the safety and efficacy of complimentary therapies and that they should be subject to the same evidence practice as other medicines."

Margaret Coats, Chief Executive of the General Chiropractic Council said: "The UK economy would achieve great financial benefit in terms of fewer absences from work. This report supports evidence that has been available for many years."